Mounting Depth sounder/Fish finder horizontally

[rockDAWG]

It got me thinking. If we mount a depth sounder/fish finder just below the surface of the water horizontally, this will warn us if any obstacle ahead of our boat. It is cheap insurance to have, I wonder if this will work.

I am thinking it out loud.

[rockDAWG]

Anyone thinking outside the box ?

[Sublime]

Try some toilet ring wax to mount one in the bilge.
I think it'd have to be a big solid object. I know if mine is at an angle, it doesn't pick up fish very well.

[miketucker]

I recently started a thread about forward looking Sonar in the Gear&Maintenance forum. A company called Interphase Tech makes such a device. I'm not sure what the difference would be between that and simply mounting a regular depth sounder facing forward. I guess the regular depth sounder is meant to look straight down, while the forward looking sonar needs to scan an 'arc' in front of you to be useful. Or maybe Interphase is just selling this simple idea with a big mark-up :-).

[celenoglu]

In my opinion forward looking sonars work the same way as normal depth sounders. The only difference is to be able to receive returning signls from the bottom. The signal will most probably bounce to forward instead of up. The other point is if you can receive the signal the depth should be recalculated. It will be the distance to the sender/receiver unit insteadof depth.

[rockDAWG]

Obviously, by mounting a depth sounder or fish finder horizontally facing out from the bow is to detect any obstacle directly in front of the boat.

The concern I have always is the floating object such a big trunk of tree or a floating container box in the middle of the ocean especially in the moonless nite. i can set the depth sounder alarm at 100 meters to sound a warning alarm.

Although the depth sounder is not a scope to scan a prefixed arc, the back and forth motion of bow will provide sufficient coverage for the sounder to work for the intended purpose. I beleive it should work.

Or maybe Interphase is just selling this simple idea with a big mark-up :-).

yes, that is what I am afraid of. When comes to yachting, the manufacture multiply the profit by 10 fold. For example, IR function in the camera or video camcorder come with the IR function in their sensor. All these cameras can convert to IR cam with little or no cost. When Garmin got the idea, they build and sell there IR camcorder for boat for 3 to 4K. It is absurd.

[centaursailor]

Originally Posted by miketucker

Or maybe Interphase is just selling this simple idea with a big mark-up :-).

I,m thinking you might be right.

Maybe a fish finder set at a shallow angle just below the waterline would give warning of an obstacle ahead. At 5kts its not going to need a huge range.
Safe sailing

[rockDAWG]

I think I will get a cheap depth sounder to experiment if this will work - proof of concept, as you will !!!

I need a sounder that has a built-in warning light so that I can easily connect to a relay to trigger a fog horn, say within 100 or 200 ft. This will be very useful for those making passage.

Hitting a floating container is very unlikely in the middle of ocean, but the thought of this scares me. If indeed I get hit, there is not much time to get out to save my own life.

My other thought is if the radar can pick up the signal of the floating container ????

[SlowButSteady]

Using a conventional depth sounder/sonar to "look" forward probably won't work in all but the calmest conditions (if then). The sounder will simply "see" any bubbles produced by surface chop and report those as the closest target. Most sounders don't really "look" in two dimensions, irrespective of what their displays indicate. They simply report the nearest return at the beginning of the "scroll". If the return is weak, and there is a stronger return from a greater depth, it will look like fish (either a fish symbol, or a "boomerang" trace). If you point one of these units forward, the display will almost certainly have so many returns from surface bubbles (i.e., so much noise) that it will be essentially "blind" to anything solid.

One demonstration of this is to look at your depth sounder in really rough water. Often times a sounder (mounted in the proper, vertical, orientation) on a small boat will intermittently display "zero" depth (or a least a very shallow depth), and the scrolling display will look like garbage. This is from the bubbles of particularly big waves passing under the boat. One can often eliminate much or most of the problem by playing with the gain and various other filters (if the unit has them) in these situations. But, if the same sounder were oriented forward there would be many more returns from an essentially infinite rage of distances, making it virtually impossible for the unit's software to differentiate any "real" targets.

[rockDAWG]

You bought out a good point. It is worth to reconsider. But the bottom line is dependent on how sensitive the detector to the bubbles and wave motion.

My feeling is most like will not work, otherwise some one must have done it. but it is worth looking into.